My superficial understanding is that \'swank-clojure\' makes \'M-x slime-connect\' possible. I mean, it gives a connection to a clojure server something like \'lein swank\'. Is
Swank is the server counterpart to swank clients like emacs SLIME and the MCLIDE lisp development environment for Macintosh. Swank servers exist for many Common Lisp implementations and Lisp dialects such as Clojure and Gambit/scheme.